/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package nl.basjes.parse.useragent.drill;

import io.netty.buffer.DrillBuf;
import org.apache.drill.exec.expr.DrillSimpleFunc;
import org.apache.drill.exec.expr.annotations.FunctionTemplate;
import org.apache.drill.exec.expr.annotations.Output;
import org.apache.drill.exec.expr.annotations.Param;
import org.apache.drill.exec.expr.annotations.Workspace;

import javax.inject.Inject;

public class UserAgentFunctions {

    @FunctionTemplate(
        name = "parse_user_agent",
        isVarArg = true,
        scope = FunctionTemplate.FunctionScope.SIMPLE
    )
    public static class UserAgentFunction implements DrillSimpleFunc {
        @Param
        org.apache.drill.exec.expr.holders.NullableVarCharHolder[] input;

        @Output
        org.apache.drill.exec.vector.complex.writer.BaseWriter.ComplexWriter outWriter;

        @Inject
        DrillBuf outBuffer;

        @Workspace
        nl.basjes.parse.useragent.UserAgentAnalyzer uaa;

        @Workspace
        java.util.List<String> allFields;

        public void setup() {
            uaa = nl.basjes.parse.useragent.drill.UserAgentAnalyzerProvider.getInstance();
            allFields = nl.basjes.parse.useragent.drill.UserAgentAnalyzerProvider.getAllFields();
        }

        public void eval() {
            org.apache.drill.exec.vector.complex.writer.BaseWriter.MapWriter queryMapWriter = outWriter.rootAsMap();

            nl.basjes.parse.useragent.AnalyzerUtilities.ParsedArguments parsedArguments =
                nl.basjes.parse.useragent.drill.UserAgentAnalyzerProvider.parseArgumentArray(input);

            nl.basjes.parse.useragent.UserAgent agent = uaa.parse(parsedArguments.getRequestHeaders());

            java.util.List<String> wantedFields = parsedArguments.getWantedFields();
            if (wantedFields.isEmpty()) {
                wantedFields = allFields;
            }

            // org.slf4j.LoggerFactory.getLogger("UDF 1").error("RESULT UDF 1\n{}", agent.toYamlTestCase(true));

            for (String fieldName : wantedFields) {
                org.apache.drill.exec.expr.holders.VarCharHolder rowHolder = new org.apache.drill.exec.expr.holders.VarCharHolder();
                String field = agent.getValue(fieldName);

                byte[] rowStringBytes = field.getBytes();
                outBuffer = outBuffer.reallocIfNeeded(rowStringBytes.length);
                outBuffer.setBytes(0, rowStringBytes);

                rowHolder.start = 0;
                rowHolder.end = rowStringBytes.length;
                rowHolder.buffer = outBuffer;

                queryMapWriter.varChar(fieldName).write(rowHolder);
            }
        }
    }

    @FunctionTemplate(name = "parse_user_agent",
        scope = FunctionTemplate.FunctionScope.SIMPLE, nulls = FunctionTemplate.NullHandling.NULL_IF_NULL)

    public static class UserAgentFieldFunction implements DrillSimpleFunc {
        @Param
        org.apache.drill.exec.expr.holders.VarCharHolder input;

        @Param
        org.apache.drill.exec.expr.holders.VarCharHolder desiredField;

        @Output
        org.apache.drill.exec.expr.holders.VarCharHolder out;

        @Inject
        DrillBuf outBuffer;

        @Workspace
        nl.basjes.parse.useragent.UserAgentAnalyzer uaa;

        public void setup() {
            uaa = nl.basjes.parse.useragent.drill.UserAgentAnalyzerProvider.getInstance();
        }

        public void eval() {
            String userAgentString = org.apache.drill.exec.expr.fn.impl.StringFunctionHelpers.getStringFromVarCharHolder(input);
            String requestedField = org.apache.drill.exec.expr.fn.impl.StringFunctionHelpers.getStringFromVarCharHolder(desiredField);

            nl.basjes.parse.useragent.UserAgent agent = uaa.parse(userAgentString);
            String field = agent.getValue(requestedField);

            byte[] rowStringBytes = field.getBytes(java.nio.charset.StandardCharsets.UTF_8);
            outBuffer = outBuffer.reallocIfNeeded(rowStringBytes.length);
            outBuffer.setBytes(0, rowStringBytes);

            out.start = 0;
            out.end = rowStringBytes.length;
            out.buffer = outBuffer;
        }
    }
}
